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Questions tagged [seismic]

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1answer
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Quality control in Seismic Acquisition - How much data is required?

When it comes to land or marine acquisition (oil exploration, for instance), I can see from literature that quality control (QC) is performed during the survey to ensure that the seismic traces ...
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1answer
38 views

converting segd data to SU format using seismic unix

I tried to convert segd format to su format using seismic unix by below command: segdread tape=1.segd > 1.su but I have an error: ...
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14 views

Calculating Incident Angles of Seismic Wave-fronts

For near/mid/far gathers, incident angles of the upcoming seismic wave-front are used for each sensor to group corresponding traces together. How are incident angles usually calculated?
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Seismic dispersion of surface-waves: overtone image and interpretation

The following image is a calculated overtone image from ParkSeis software. Note that the type of surface-wave evaluated is Rayleigh-waves. My question is this: what do the relatively high and ...
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1answer
42 views

Basic petrophysics

The following question was inspired by Effective pressure or what is the effect of presssure?, which may be accessed here: https://inside.mines.edu/UserFiles/File/CRA/2005/...
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1answer
46 views

DC component in Hilbert transform concept for seismic data

In The Leading Edge tutorial article Phase and the Hilbert transform (Purves 2014), there is the following line: So we apply a Hilbert transform by multiplying all negative frequencies by i and all ...
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0answers
20 views

How do I generate a Moho depth model from seismic refraction data?

There are several permanent seismograph stations in Eastern Canada that have been recording arrival times for over 25 years. Using refracted Pn arrival times from natural earthquakes I would like to ...
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14 views

Where to acquire Open source Seismic Data-sets

Where can I acquire seismic data sets for free with the following information: 3D Seismic data in SGY Format Well logs within the acquired seismic area The well logs containing Gamma, Density, ...
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1answer
35 views

Spectral Whitening, Seismic Interferometry

What is the role of spectral whitening in the processing step done before cross-correlations in seismic interferometry?
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0answers
33 views

Seismology - PPV / VDV from geophone waveform data

I'm using an inexpensive seismometer to try and measure the effects of local HGV traffic on buildings. The device is connected to a Raspberry PI that has a Cirrus Logic Audio Card. The signal is fed ...
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2answers
81 views

Seismic dispersion: What does it really mean and what causes it?

Body waves (to some extent) and especially surface waves show dispersive characteristics during propagation. In Dr. Christopher Liner's book [Elements of Seismic Dispersion (2012)], this phenomenon is ...
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1answer
47 views

What does 'reghosted' mean in a seismic cube label?

I came across to a seismic volume labeled as reghosted. In my understanding, a seismic survey is deghosted as part of a processing step. Then I wonder why one would like to reghosted the data? Is ...
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29 views

Which wavelet for acoustic inversion?

If I have seismic data obtained with an explosive source (i.e. minimum phase wavelet), should I re-process the data into zero-phase data to perform an acoustic impedance inversion?
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1answer
94 views

Open source well information viewer

I am in the middle of a hobbyist experiment and would like suggestions on an open source HTML viewer for mud loggging, FMIs, lithology and seismic. I have used INT before but for this project I would ...
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0answers
42 views

Interpretation of horizon display

I am currently working on a project that involves using seismic attributes as input parameters in a neural network for estimation of porosity and permeability for a reservoir. Now, I need to correlate ...
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1answer
35 views

DC component: Seismic inversion

Multiple papers (for example, Limitations on impedance inversion of band-limited reflection data Gosh[2000]) and textbooks covering seismic inversion mention a necessary component of any seismic ...
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1answer
30 views

Seismic inversion: High-Frequency approximation

In numerous textbooks and papers, the phrase "high-frequency" approximation is used in regards to different types of seismic inversion. What exactly is meant by this? Also, what are the implications ...
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1answer
125 views

Seismic migration concepts

In Dr Hua-Wei Zhou's book Practical Seismic Data Analysis (2014), he includes and explains figures from previous classic works (i.e. Schneider, 1971) in order to describe migration from a fundamental ...
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1answer
82 views

Seismic AVO/AVA concepts

I have a basic question concerning AVO, AVA, and reflections. What is the difference between AVO/AVA and obliquity factors from a given reflection from a point in the subsurface? If there is a ...
3
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1answer
145 views

Which type of seismic sensors usually used in Earthquake Early Warning?

As I'm a newbie in seismology and related area, I would like to know which type of seismic sensors usually used in earthquake early warning systems?
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1answer
397 views

What is the relationship between raw seismic data, CMP Stacking, NMO & Machine Learning

I recently joined a geophysics project to assist with some of their machine learning modeling but am trying to gather the domain knowledge required to participate. Something I don't quite understand ...
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0answers
45 views

Problem in identification of seismic event?

I have taken the following synthetic seismogram, generated using Marmousi model, from the Madagascar website. I could not understand the origin of linear events (present in shot3 after 2 sec) and ...
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0answers
89 views

Does seismic anisotropy follow stratigraphy?

This question is in the context of velocity model building for reflection seismic imaging (between 0km and 10km in a sedimentary basin). This is really a rock physics question disguised as an imaging ...
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0answers
54 views

Theorist speculate about dozens of loud atmospheric booms across globe

Theorist speculate on the dozens of loud atmospheric booms across globe. Has any recognized institutions offered a plausible explanation as of now?
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1answer
132 views

Seismic data spectral analysis

The two images below correspond to two processed seismic cross-sections. My question is this: why at/near 0 Hz is there "lots" of seismic energy still present? Most if not all of the lower end of the ...
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1answer
52 views

What is seismic stretch in geophysical method?

What is seismic stretch in geophysical method ?
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1answer
1k views

SEGD and SEGY recorded data

What is the difference between a segd recorded data and a segy recorded data and can we convert from segd to segy and vice versa?
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333 views

Effects of Mexican Earthquake in San Andreas Fault Line

Could the recent 8.1 Magnitude Earthquake at the Cocos and Nazca plates off the Mexican coast have a knock on effect to the Pacific and Juan de Fuca Plates further north at the San Andreas Fault Line?
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3answers
662 views

What are the distinguishing features of an “artificial seismic wave” (e.g. a large underground explosion)

IN the NPR news item North Korea Possibly Conducts Sixth Nuclear Test, South Korea Says: The U.S. Geological Survey says it detected a 6.3 magnitude "possible explosion" near Sungjibaegam, North ...
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0answers
77 views

Linear vs nonlinear seismic inversion

I am using the MATLAB script BLIMP (Ferguson and Margrave, 1995) to invert SH-wave data for shear-impedance. Is this inversion scheme a linear or non-linear process? There are certainly non-linear ...
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1answer
58 views

Seismic Reflectivity and Fractal (Random) Behavior

*One of the fundamental assumptions of the convolutional model (and subsequently a lot of deconvolution methods) is that reflectivity is a purely random (or "white") process. Overall, the only ...
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0answers
34 views

Shear-Waves and Stress

-I study the near-surface via seismic reflection surveying with shear-waves. I know that effective stress strongly influences the velocity behavior of any body wave in the near-surface (5 - 50 m). My ...
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0answers
69 views

The phase of a seismic source

There are different seismic sources for both land and marine acquisition surveys. Measuring the spectral characteristics (phase, frequency, amplitude, etc.) is a critical part of evaluating the ...
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1answer
143 views

Amplitude scaling in seismic inversion

I've been testing how amplitude scaling subsequently affects the results of gapped/non-gapped deconvolution and an impedance inversion algorithm called BLIMP (Ferguson and Margrave, 1996). Indeed, ...
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1answer
223 views

Post-stack seismic impedance (and amplitude) inversion confusion

Yilmaz (2016) briefly explains - along with a nice accompanied image/diagram - the main categories of seismic inversion. He claims there are four: travel-time, waveform, hybrid, and join inversion. ...
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1answer
140 views

What is trace-based seismic Inversion

Looking through different literature articles and books concerning seismic inversion - mostly post-stack - phrases like "trace-based" and "model-based" keep appearing. I know that model-based in when ...
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1answer
633 views

Can large earthquakes happen few times at same place(in days)

I want to know if large earthquakes can happen twice in the same place? I live in Istanbul/Turkey. In Canakkale/Turkey too many earthquakes happen for days! I know it is normal for this region but 4.8 ...
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0answers
232 views

Creating SEGY header for multishot seismic synthetic data

I am trying to convert synthetic shot gathers (n shots) for a 2D model into a single SEGY file. For an illustration of geometry, I have attached a snap of my sources (in red) and receivers (in blue) ...
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392 views

Analytical solution for seismic wavefield in MATLAB

I have been trying to evaluate the analytical solution for a wave travelling in a homogeneous, infinite media. For a given source $S(t)$, the wave-field can be calculated at a distance $r$, for a ...
2
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1answer
294 views

Velocity from time and depth seismic images

I have a seismic dataset that contains a depth-migrated seismic (amplitude) volume in depth and then the exact same volume converted to time using the migration velocities. Unfortunately, I do not ...
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2answers
107 views

What percentage of the earth's surface is covered by 2D or 3D reflection seismic data?

It was recently asserted to me that we have no idea what Planet Earth really looks like below our feet. I responded that (mainly oil-industry) seismic data covers a vast area and so actually we have a ...
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0answers
145 views

How to do inverse Fourier transformation with Seismic Unix?

I convert data from $t$-$x$ domain to $f$-$k$ domain to do dip filter using sudipfilt command. After that it should return to the $t$-$x$ domain. Which command ...
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1answer
654 views

Open source seismic refraction processing

What I am in search of is an open source tool to pick first arrivals, plot travel-time curves, and perform simple velocity modeling. I am experimenting with seismic refraction to identify shallow ...
3
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1answer
377 views

Detecting seismic waves using Software Defined Radio

I understand about physic and waves, but I am a totally rookie in this topic. I was wondering which are the typical frequency ranges of the S-waves, P-waves and surface waves. My idea would be to ...
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3answers
209 views

Why is a mild earthquake often mistaken as dizziness or vertigo?

Is it due to the longitudinal nature of the seismic waves? When a heavy bus or truck goes by at high-speed, the shaking in nearby ground is not mistaken as dizziness, rather the feet and body feel a ...
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0answers
119 views

Can non-antipodal Chicxulub impact seismic wave be connected to Rio Grande Rift and Laramide Orogeny?

I have conducted a brief survey of Internet sources and cannot locate any definite discussion of a possible connection between the Chicxulub impact and the inception or acceleration of the Rio Grande ...
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0answers
71 views

Unwanted oscillations in Synthetic seismogram

I have generated a synthetic seismogram using FDTD elastic velocity-stress formulation on a staggered grid. I can't understand origin of oscillations modulating on seismogram. Is it a result of ...
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3answers
606 views

Gaussian wavelet generation with a given frequency

How can I generate a Gaussian wavelet (time domain) with a given central frequency. I mean if I take the Fourier Transform then its spectrum should be around that given central frequency instead of ...
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1answer
65 views

Where to start with P190s Seismic Navigation Files?

I have a few P190s navigation files from a 2D reflection seismic acquisition shoot and wondering what the best way was to extract UTM's (or latitude and longitude) and depth. I am reading through the ...
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1answer
174 views

Cross-line fold of a towed-streamer survey

On page 29 of the book 3D Seismic Survey Design by Gijs O. Vermeer, Vermeer says that the equation for a maximum fold in a 3D survey is the following: $M = M_i \times M_c$ where $M_i$ is the inline ...